"The process of sketching and drawing can involve proportioning, which is the gauging and sizing of the subject elements. The simplest device for doing this may be the shaft of a pencil, while more accurate devices or tools include dividers and sewing gauges. A divider is similar to a compass and can be easily adjusted to compare sizes and proportions when working from photographs. A sewing gauge can be used in a similar manner to compare sizes and proportions when working from photographs or a live model."